Conventionally, various vehicles, which include electric motors as drive sources, have been known. In general, in this kind of a vehicle, a braking apparatus includes a hydraulic wheel braking force generating means (so-called hydraulic brake system) that generates wheel braking forces (hydraulic wheel braking forces) on respective wheels by hydraulic forces and an electric motor that can be operated as a generator in order to generate regenerative wheel braking forces on driving wheels. Usually, in the braking apparatus, the hydraulic wheel braking forces and the regenerative wheel braking forces are adjusted so that a requested vehicle braking force, which corresponds to the driver's operation of a brake pedal, is applied to a vehicle. Accordingly, the hydraulic wheel braking force generating means is provided with a working fluid pressure adjusting unit (so-called brake actuator). The working fluid pressure adjusting unit transmits hydraulic pressure, which is generated by the operating pressure applied to the brake pedal by a driver, to respective wheels as it is, or transmits the hydraulic pressure to the respective wheels after increasing/decreasing the hydraulic pressure.
For example, as the above-mentioned vehicle, there is a hybrid vehicle disclosed in Patent Document 1 that drives front wheels by an engine (prime mover) and drives rear wheels by a motor (electric motor). Further, the following Patent Document 2 discloses a hybrid vehicle that drives one of front and rear wheels by an engine (prime mover) and drives the other thereof by a motor (electric motor).
Meanwhile, the following Patent Document 3 discloses a technique that increases the braking forces of front wheels by applying engine braking to the front wheels in order to avoid rear wheel lock in a vehicle that is driven by an engine. Further, the following Patent Document 4 discloses a technique that controls a gear ratio or a shift point of a transmission means so as to maximize the amount of regenerative power becomes maximum in a range where the sum of a regenerative braking force and an engine braking force does not exceed a predetermined value or a braking force requested by a driver.    Patent Document 1: Japanese Patent Application Laid-open No. 2001-234774    Patent Document 2: Japanese Patent Application Laid-open No. 2004-52625    Patent Document 3: Japanese Patent Application Laid-open No. 2005-145430    Patent Document 4: Japanese Patent Application Laid-open No. 2003-74685